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Linkprüfung – Verwaltungskonto

Benachrichtigungssymbol

Das Skript "Linkprüfung" für Google Ads-Verwaltungskonten erweitert das Skript Linkprüfung für einzelne Konten so, dass es für mehrere Konten in einem Verwaltungskonto ausgeführt werden kann.

Im Zuge der Weiterentwicklung einer Website werden neue Seiten hinzugefügt, alte Seiten werden entfernt, Links werden fehlerhaft und repariert. Für viele Werbetreibende ist es eine ständige Herausforderung, eine Google Ads-Kampagne mit der Website synchron zu halten. Live-Anzeigen können auf nicht vorhandene Seiten verweisen und der Werbetreibende bezahlt am Ende für Klicks, die 404-Fehler verursachen.

Mit der Funktion „Linkprüfung“ wird dieses Problem behoben, indem alle Anzeigen, Keywords und Sitelinks durchlaufen werden. Außerdem wird überprüft, ob die URLs der Seiten den Fehler „Seite nicht gefunden“ oder andere Fehlerantworten zurückgeben. Außerdem werden Sie per E-Mail benachrichtigt, wenn Fehlerantworten gefunden werden, und die Analyseergebnisse werden in einer Tabelle gespeichert.

Einige Konten enthalten möglicherweise eine große Anzahl von URLs, die aufgrund von Zeitlimits für die Ausführung oder quotas nicht alle bei einer einzelnen Ausführung überprüft werden können. Das Skript ist so konzipiert, dass es seinen Fortschritt über mehrere Ausführungen hinweg verfolgt und nur URLs prüft, die es zuvor noch nicht überprüft hat. Im Skript wird der Begriff „Analyse“ für einen vollständigen Durchlauf aller URLs verwendet, auch wenn mehrere Durchläufe erforderlich sind.

Konfiguration

Die wichtigsten Optionen des Skripts können in einer Tabelle festgelegt werden.

Screenshot einer Tabelle

Umfang: Bestimmt, ob das Skript Anzeigen, Keywords und Sitelinks prüft und ob das Skript diese auch dann prüft, wenn sie pausiert sind. Die meisten Nutzer sollten alle drei hinzufügen, damit alle URLs geprüft werden. Normalerweise ist es jedoch nicht erforderlich, pausierte Entitäten zu überprüfen.
Gültige Antwortcodes: Die Liste der als gültig erachteten HTTP-Antwortcodes. Für die meisten Nutzer sollte nur 200 ein gültiger Antwortcode sein.
E-Mail nach jeder Skriptausführung senden: Wenn Sie diese Option aktivieren, erhalten Sie nach jeder Ausführung eine E-Mail mit einer Zusammenfassung der URLs, die überprüft wurden. So werden Sie frühzeitig über URL-Fehler benachrichtigt, anstatt warten zu müssen, bis alle URLs überprüft wurden (was mehrere Ausführungen in Anspruch nehmen kann).
E-Mail nach Abschluss der gesamten Analyse senden: Wenn Sie diese Option aktivieren, erhalten Sie per E-Mail eine konsolidierte Zusammenfassung, nachdem alle URLs überprüft wurden.
E-Mail senden, auch wenn keine Fehler gefunden werden: Wenn Sie diese Option aktivieren, erhalten Sie eine E-Mail vom Skript (basierend auf den beiden vorherigen Optionen), auch wenn keine Fehler gefunden wurden. Die meisten Nutzer ziehen es vor, nur bei Fehlern eine E-Mail zu erhalten. Wenn Sie jedoch eine E-Mail erhalten, selbst wenn keine Fehler vorliegen, kann dies hilfreich sein, um sicherzustellen, dass das Skript wie geplant ausgeführt wird.
Gültige URLs in Tabelle speichern: Wenn Sie diese Option aktivieren, speichert das Skript jede überprüfte URL in der Tabelle, nicht nur die URLs mit Fehlern. Die meisten Nutzer bevorzugen es, nur fehlerhafte URLs zu speichern, aber einige möchten möglicherweise die gesamte Anzahl der URLs sehen, die vom Skript geprüft wurden.
Tage zwischen Analysen: Mit dieser Option steuern Sie, wie oft das Skript eine neue Analyse der gesamten URL-Liste beginnt. Mit dieser Option legen Sie die Mindestanzahl von Tagen zwischen Analysen fest. Die tatsächliche Anzahl kann höher sein, wenn eine Analyse mehr Zeit in Anspruch nimmt (z. B. bei einer großen Anzahl von URLs). Weitere Informationen finden Sie unter Planung.

Erweiterte Linkvalidierung

Für einige Anwendungsfälle reicht es unter Umständen nicht aus, zu wissen, dass die URL eine gültige Seite zurückgibt. Angenommen, eine Produktseite enthält den Text „Produkt eingestellt“. In diesem Fall könnten Sie die Seite als fehlerhaften Link melden.

Das Skript bietet zwei Validierungsoptionen:

Fehlerstrings

Legen Sie für Use simple filter filter string (Einfachen Abgleich von Fehlerstrings verwenden) den Wert Yes fest, um nach Vorkommen der Liste von Strings zu suchen, die in Fehlerstrings definiert sind. Jedes Vorkommen auf einer Webseite markiert die Seite als fehlerhaft.

Benutzerdefinierte Bestätigung

Für noch mehr Flexibilität kann für jede URL und Antwort eine benutzerdefinierte JavaScript-Validierungsfunktion verwendet werden. So können Sie beispielsweise prüfen, ob der Titel einer Webseite Ihren Markennamen enthält:

Legen Sie für Benutzerdefinierte Validierungsfunktion verwenden den Wert Yes fest.

Fügen Sie Ihre benutzerdefinierte Validierungslogik in eine Funktion am Anfang des Skripts ein:

function isValidResponse(url, response, options, entityDetails) {
  // Your custom logic here, returning true for valid links, false otherwise.
  // ...
}

Eine einfache Implementierung mit Beispielen für den Zugriff auf den Antworttext ist bereits vorhanden.

Wird geplant

Bei jeder Ausführung des Skripts wird automatisch erkannt, ob eine laufende Analyse fortgesetzt oder die letzte Analyse abgeschlossen und eine neue gestartet werden muss (basierend auf der Option Tage zwischen Analysen). Unabhängig davon, wie oft Sie eine neue Analyse starten möchten, planen Sie das Skript für die stündliche Ausführung, damit jede Analyse Ihre URLs so schnell wie möglich durchläuft.

Legen Sie beispielsweise für Tage zwischen Analysen den Wert 1 fest, damit das Skript höchstens einmal pro Tag eine neue Analyse startet. Wenn das Skript für eine stündliche Ausführung geplant ist und alle URLs in weniger als einem Tag überprüft wurden, werden nachfolgende Ausführungen sofort bis zum nächsten Tag beendet, wenn es an der Zeit ist, eine neue Analyse zu starten.

Funktionsweise

Das Skript erstellt ein Label, um den Fortschritt zu verfolgen, und wendet es auf Ihre Anzeigen, Keywords und Sitelinks an, nachdem es diese überprüft hat. Das Skript kann dann überprüfte URLs bei der nächsten Ausführung identifizieren. Sobald eine Analyse abgeschlossen ist (alle URLs überprüft wurden), löscht das Skript das Label für eine neue Analyse.

Das Skript verwendet UrlFetchApp, um finale URLs und finale URLs für Mobilgeräte zu prüfen.

Einrichtung

Klicken Sie auf die Schaltfläche unten, um das tabellenbasierte Skript in Ihrem Google Ads-Konto zu erstellen.

Skriptvorlage installieren
Klicken Sie auf die Schaltfläche unten, um eine Kopie der Tabellenvorlage zu erstellen.

Tabellenvorlage kopieren
Aktualisieren Sie spreadsheet_url im Script.
Planen Sie das Skript für eine stündliche Ausführung.

Quellcode

// Copyright 2015, Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/**
 * @name Link Checker - Manager Accounts
 *
 * @overview The Link Checker script iterates through the ads, keywords, and
 *     sitelinks in your manager account hierarchy and makes sure their URLs
 *     do not produce "Page not found" or other types of error responses. See
 *     https://developers.google.com/google-ads/scripts/docs/solutions/manager-link-checker
 *     for more details.
 *
 * @author Google Ads Scripts Team [adwords-scripts@googlegroups.com]
 *
 * @version 3.1
 *
 * @changelog
 * - version 3.1
 *   - Split into info, config, and code.
 * - version 3.0
 *   - Updated to use new Google Ads scripts features.
 * - version 2.2
 *   - Added support for failure strings and custom validation functions.
 * - version 2.1
 *   - Added expansion of conditional ValueTrack parameters (e.g. ifmobile).
 *   - Added expanded text ad and other ad format support.
 * - version 2.0.3
 *   - Added validation for external spreadsheet setup.
 * - version 2.0.2
 *   - Allow the custom tracking label to include spaces.
 * - version 2.0.1
 *   - Catch and output all UrlFetchApp exceptions.
 *   - Completely revised the script to work on larger accounts and hierarchies.
 * - version 1.3
 *   - Enhanced to include ad group sitelinks.
 *   - Updated to track completion across runs and send at most one email
 *     per day.
 * - version 1.2
 *   - Remove label flushing code from the script.
 * - version 1.1
 *   - Remove some debug code.
 * - version 1.0
 *   - Released initial version.
 */
/**
 * Configuration to be used for the Link Checker.
 */

CONFIG = {
  // URL of the spreadsheet template.
  // This should be a copy of
  // https://docs.google.com/spreadsheets/d/1iO1iEGwlbe510qo3Li-j4KgyCeVSmodxU6J7M756ppk/copy.
  // Make sure the sheet is owned by or shared with same Google user executing the script
  'spreadsheet_url': 'YOUR_SPREADSHEET_URL',

  // Array of addresses to be alerted via email if issues are found.
  'recipient_emails': ['YOUR_EMAIL_HERE'],

  // Label to use when a link has been checked.
  'label': 'LinkChecker_Done',

  // A list of ManagedAccountSelector conditions to restrict the population
  // of child accounts that will be processed. Leave blank or comment out
  // to include all child accounts.
  'account_conditions': [],

  // Number of seconds to sleep after each URL request. Use this throttle
  // to reduce the load that the script imposes on your web server(s).
  'throttle_seconds': 0,

  // Number of seconds before timeout that the script should stop checking URLs
  // to make sure it has time to output its findings.
  'timeout_buffer_seconds': 120,

  'advanced_options': {
    /**
     * Parameters controlling the script's behavior after hitting a UrlFetchApp
     * QPS quota limit.
     */
    'quota_config': {
      // Initial number of milliseconds to sleep.
      'INIT_SLEEP_TIME_MILLIS': 250,
      // Multiplicative factor to increase sleep time by on each retry.
      'BACKOFF_FACTOR': 2,
      // Maximum number of tries for a single URL.
      'MAX_TRIES': 5
    }
  }
};
/**
 * Performs custom validation on a URL, with access to details such as the URL,
 * the response from the server, configuration options and entity Details.
 *
 * To use, the "Use Custom Validation" option in the configuration spreadsheet
 * must be set to "Yes", and your custom validation code implemented within the
 * below function.
 *
 * See the documentation for this solution for further details.
 *
 * @param {string} url The URL being checked.
 * @param {!HTTPResponse} response The response object for the request.
 * @param {!Object} options Configuration options.
 * @param {!Object} entityDetails Details of the associated Ad / Keywords etc.
 * @return {boolean} Return true if the URL and response are deemed valid.
 */
function isValidResponse(url, response, options, entityDetails) {
  /*
     Some examples of data that can be used in determining the validity of this
     URL. This is not exhaustive and there are further properties available.
  */

  // The HTTP status code, e.g. 200, 404
  // const responseCode = response.getResponseCode();

  // The HTTP response body, e.g. HTML for web pages:
  // const responseText = response.getContentText();

  // The failure strings from the configuration spreadsheet, as an array:
  // const failureStrings = options.failureStrings;

  // The type of the entity associated with the URL, e.g. Ad, Keyword, Sitelink.
  // const entityType = entityDetails.entityType;

  // The campaign name
  // const campaignName = entityDetails.campaign;

  // The ad group name, if applicable
  // const adGroupName = entityDetails.adGroup;

  // The ad text, if applicable
  // const adText = entityDetails.ad;

  // The keyword text, if applicable
  // const keywordText = entityDetails.keyword;

  // The sitelink link text, if applicable
  // const sitelinkText = entityDetails.sitelink;

  /*
   Remove comments and insert custom logic to determine whether this URL and
   response are valid, using the data obtained above.

   If valid, return true. If invalid, return false.
  */

  // Placeholder implementation treats all URLs as valid
  return true;
}

const MILLISECONDS_PER_SECOND = 1000;
const QUOTA_CONFIG = CONFIG.advanced_options.quota_config;

const SPREADSHEET_URL = CONFIG.spreadsheet_url;
const RECIPIENT_EMAILS = CONFIG.recipient_emails;
const LABEL = CONFIG.label;
const THROTTLE_SECONDS = CONFIG.throttle_seconds;
const TIMEOUT_BUFFER_SECONDS = CONFIG.timeout_buffer_seconds;
const ACCOUNT_CONDITIONS = CONFIG.account_conditions;

/**
 * Exceptions that prevent the script from finishing checking all URLs in an
 * account but allow it to resume next time.
 */
const EXCEPTIONS = {
  QPS: 'Reached UrlFetchApp QPS limit',
  LIMIT: 'Reached UrlFetchApp daily quota',
  TIMEOUT: 'Approached script execution time limit'
};

/**
 * Named ranges in the spreadsheet.
 */
const NAMES = {
  CHECK_AD_URLS: 'checkAdUrls',
  CHECK_KEYWORD_URLS: 'checkKeywordUrls',
  CHECK_SITELINK_URLS: 'checkSitelinkUrls',
  CHECK_PAUSED_ADS: 'checkPausedAds',
  CHECK_PAUSED_KEYWORDS: 'checkPausedKeywords',
  CHECK_PAUSED_SITELINKS: 'checkPausedSitelinks',
  VALID_CODES: 'validCodes',
  EMAIL_EACH_RUN: 'emailEachRun',
  EMAIL_NON_ERRORS: 'emailNonErrors',
  EMAIL_ON_COMPLETION: 'emailOnCompletion',
  SAVE_ALL_URLS: 'saveAllUrls',
  FAILURE_STRINGS: 'failureStrings',
  FREQUENCY: 'frequency',
  DATE_STARTED: 'dateStarted',
  DATE_COMPLETED: 'dateCompleted',
  DATE_EMAILED: 'dateEmailed',
  NUM_ERRORS: 'numErrors',
  RESULT_HEADERS: 'resultHeaders',
  ARCHIVE_HEADERS: 'archiveHeaders',
  USE_SIMPLE_FAILURE_STRINGS: 'useSimpleFailureStrings',
  USE_CUSTOM_VALIDATION: 'useCustomValidation'
};

function main() {
  const spreadsheet = validateAndGetSpreadsheet(SPREADSHEET_URL);
  validateEmailAddresses();
  spreadsheet.setSpreadsheetTimeZone(AdsApp.currentAccount().getTimeZone());

  const options = loadOptions(spreadsheet);
  const status = loadStatus(spreadsheet);

  if (!status.dateStarted) {
    // This is the very first execution of the script.
    startNewAnalysis(spreadsheet);
  } else if (status.dateStarted > status.dateCompleted) {
    console.log(`Resuming work from a previous execution.`);
  } else if (dayDifference(status.dateStarted, new Date()) <
             options.frequency) {
    console.log(`Waiting until ${options.frequency} days have elapsed since ` +
                `the start of the last analysis.`);
    return;
  } else {
    // Enough time has passed since the last analysis to start a new one.
    removeLabelsInAccounts();
    removeAccountLabels([LABEL]);
    startNewAnalysis(spreadsheet);
  }

  ensureAccountLabels([LABEL]);

  // Get up to 50 accounts that have not yet had all of their URLs checked.
  const accountSelector = getAccounts(false).withLimit(50);
  if (accountSelector.get().hasNext()) {
    accountSelector
        .executeInParallel('processAccount', 'processResults', JSON.stringify(options));
  } else {
    processResults([]);
  }
}

/**
 * Retrieves all accounts that either have had their URLs checked or need to
 * have their URLs checked.
 *
 * @param {boolean} isChecked True to get accounts that have been checked
 *     already, false to get accounts that have not have been checked already.
 *     Ignored if the label does not exist.
 * @return {Object} An account selector.
 */
function getAccounts(isChecked) {
  let accountSelector = AdsManagerApp.accounts();
  
  const accountLabel = getAccountLabel(LABEL);

  if (accountLabel) {
    accountSelector = accountSelector
      .withCondition(`customer_client.applied_labels ${(isChecked ? `CONTAINS ANY` : `CONTAINS NONE`)}` +
          ` ("${accountLabel.getResourceName()}")`);
  }

  if (ACCOUNT_CONDITIONS) {
    for (const condition of ACCOUNT_CONDITIONS) {
      accountSelector =
          accountSelector.withCondition(condition);
    }
  }

  return accountSelector;
}

/**
 * Removes the tracking in each account that was previously analyzed, thereby
 * clearing that account for a new analysis.
 */
function removeLabelsInAccounts() {
  const managerAccount = AdsApp.currentAccount();
  const accounts = getAccounts(true).get();

  for (const account of accounts) {
    AdsManagerApp.select(account);
    removeLabels([LABEL]);
  }

  AdsManagerApp.select(managerAccount);
}

/**
 * Performs the link checking analysis on the current account.
 *
 * @param {string} options Options from the spreadsheet as JSON.
 * @return {string} JSON stringified results of the analysis.
 */
function processAccount(options) {
  return JSON.stringify(analyzeAccount(JSON.parse(options)));
}

/**
 * Consolidates results from each account and outputs them.
 *
 * @param {Array.<Object>} executionResults A list of ExecutionResult objects.
 */
function processResults(executionResults) {
  const spreadsheet = SpreadsheetApp.openByUrl(SPREADSHEET_URL);
  const options = loadOptions(spreadsheet);
  const results = {
    urlChecks: [],
    didComplete: true
  };

  for (const result of executionResults) {
    if (!result.getError()) {
      const accountResult = JSON.parse(result.getReturnValue());
      results.urlChecks = results.urlChecks.concat(accountResult.urlChecks);
      results.didComplete = results.didComplete && accountResult.didComplete;

      if (accountResult.didComplete) {
        AdsManagerApp.accounts()
            .withIds([result.getCustomerId()])
            .get()
            .next()
            .applyLabel(LABEL);
      }
    } else {
      console.log(`Processing for ${result.getCustomerId()} failed.`);
    }
  }

  // The entire analysis is not complete if there are any accounts that have
  // not been labeled (i.e., the account was not started, or not all URLs in
  // the account have been checked).
  results.didComplete = results.didComplete &&
      !getAccounts(false).get().hasNext();

  outputResults(results, options);
}

/**
 * Checks as many new URLs as possible that have not previously been checked,
 * subject to quota and time limits.
 *
 * @param {Object} options Dictionary of options.
 * @return {Object} An object with fields for the URLs checked and an indication
 *     if the analysis was completed (no remaining URLs to check).
 */
function analyzeAccount(options) {
  // Ensure the label exists before attempting to retrieve already checked URLs.
  ensureLabels([LABEL]);

  const checkedUrls = getAlreadyCheckedUrls(options);
  const urlChecks = [];
  let didComplete = false;

  try {
    // If the script throws an exception, didComplete will remain false.
    didComplete = checkUrls(checkedUrls, urlChecks, options);
  } catch(e) {
    if (e == EXCEPTIONS.QPS ||
        e == EXCEPTIONS.LIMIT ||
        e == EXCEPTIONS.TIMEOUT) {
      console.log(`Stopped checking URLs early because: ${e}`);
      console.log(`Checked URLs will still be output.`);
    } else {
      throw e;
    }
  }

  return {
    urlChecks: urlChecks,
    didComplete: didComplete
  };
}

/**
 * Outputs the results to a spreadsheet and sends emails if appropriate.
 *
 * @param {Object} results An object with fields for the URLs checked and an
 *     indication if the analysis was completed (no remaining URLs to check).
 * @param {Object} options Dictionary of options.
 */
function outputResults(results, options) {
  const spreadsheet = SpreadsheetApp.openByUrl(SPREADSHEET_URL);

  const numErrors = countErrors(results.urlChecks, options);
  console.log(`Found ${numErrors} errors this execution.`);

  saveUrlsToSpreadsheet(spreadsheet, results.urlChecks, options);

  // Reload the status to get the total number of errors for the entire
  // analysis, which is calculated by the spreadsheet.
  status = loadStatus(spreadsheet);

  if (results.didComplete) {
    spreadsheet.getRangeByName(NAMES.DATE_COMPLETED).setValue(new Date());
    console.log(`Found ${status.numErrors} errors across the entire analysis.`);
  }

  if (RECIPIENT_EMAILS) {
    if (!results.didComplete && options.emailEachRun &&
        (options.emailNonErrors || numErrors > 0)) {
      sendIntermediateEmail(spreadsheet, numErrors);
    }

    if (results.didComplete &&
        (options.emailEachRun || options.emailOnCompletion) &&
        (options.emailNonErrors || status.numErrors > 0)) {
      sendFinalEmail(spreadsheet, status.numErrors);
    }
  }
}

/**
 * Loads data from a spreadsheet based on named ranges. Strings 'Yes' and 'No'
 * are converted to booleans. One-dimensional ranges are converted to arrays
 * with blank cells omitted. Assumes each named range exists.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 * @param {Array.<string>} names A list of named ranges that should be loaded.
 * @return {Object} A dictionary with the names as keys and the values
 *     as the cell values from the spreadsheet.
 */
function loadDatabyName(spreadsheet, names) {
  const data = {};

  for (const name of names) {
    const range = spreadsheet.getRangeByName(name);

    if (range.getNumRows() > 1 && range.getNumColumns() > 1) {
      // Name refers to a 2d range, so load it as a 2d array.
      data[name] = range.getValues();
    } else if (range.getNumRows() == 1 && range.getNumColumns() == 1) {
      // Name refers to a single cell, so load it as a value and replace
      // Yes/No with boolean true/false.
      data[name] = range.getValue();
      data[name] = data[name] === 'Yes' ? true : data[name];
      data[name] = data[name] === 'No' ? false : data[name];
    } else {
      // Name refers to a 1d range, so load it as an array (regardless of
      // whether the 1d range is oriented horizontally or vertically).
      const isByRow = range.getNumRows() > 1;
      const limit = isByRow ? range.getNumRows() : range.getNumColumns();
      const cellValues = range.getValues();

      data[name] = [];
      for (let j = 0; j < limit; j++) {
        const cellValue = isByRow ? cellValues[j][0] : cellValues[0][j];
        if (cellValue) {
          data[name].push(cellValue);
        }
      }
    }
  }

  return data;
}

/**
 * Loads options from the spreadsheet.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 * @return {Object} A dictionary of options.
 */
function loadOptions(spreadsheet) {
  return loadDatabyName(spreadsheet,
      [NAMES.CHECK_AD_URLS, NAMES.CHECK_KEYWORD_URLS,
       NAMES.CHECK_SITELINK_URLS, NAMES.CHECK_PAUSED_ADS,
       NAMES.CHECK_PAUSED_KEYWORDS, NAMES.CHECK_PAUSED_SITELINKS,
       NAMES.VALID_CODES, NAMES.EMAIL_EACH_RUN,
       NAMES.EMAIL_NON_ERRORS, NAMES.EMAIL_ON_COMPLETION,
       NAMES.SAVE_ALL_URLS, NAMES.FREQUENCY,
       NAMES.FAILURE_STRINGS, NAMES.USE_SIMPLE_FAILURE_STRINGS,
       NAMES.USE_CUSTOM_VALIDATION]);
}

/**
 * Loads state information from the spreadsheet.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 * @return {Object} A dictionary of status information.
 */
function loadStatus(spreadsheet) {
  return loadDatabyName(spreadsheet,
      [NAMES.DATE_STARTED, NAMES.DATE_COMPLETED,
       NAMES.DATE_EMAILED, NAMES.NUM_ERRORS]);
}

/**
 * Saves the start date to the spreadsheet and archives results of the last
 * analysis to a separate sheet.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 */
function startNewAnalysis(spreadsheet) {
  console.log(`Starting a new analysis.`);

  spreadsheet.getRangeByName(NAMES.DATE_STARTED).setValue(new Date());

  // Helper method to get the output area on the results or archive sheets.
  function getOutputRange(rangeName) {
    const headers = spreadsheet.getRangeByName(rangeName);
    return headers.offset(1, 0, headers.getSheet().getDataRange().getLastRow());
  }

  getOutputRange(NAMES.ARCHIVE_HEADERS).clearContent();

  const results = getOutputRange(NAMES.RESULT_HEADERS);
  results.copyTo(getOutputRange(NAMES.ARCHIVE_HEADERS));

  getOutputRange(NAMES.RESULT_HEADERS).clearContent();
}

/**
 * Counts the number of errors in the results.
 *
 * @param {Array.<Object>} urlChecks A list of URL check results.
 * @param {Object} options Dictionary of options.
 * @return {number} The number of errors in the results.
 */
function countErrors(urlChecks, options) {
  let numErrors = 0;

  for (const urlCheck of urlChecks) {
    if (options.validCodes.indexOf(urlCheck.responseCode) == -1) {
      numErrors++;
    }
  }

  return numErrors;
}

/**
 * Saves URLs for a particular account to the spreadsheet starting at the first
 * unused row.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 * @param {Array.<Object>} urlChecks A list of URL check results.
 * @param {Object} options Dictionary of options.
 */
function saveUrlsToSpreadsheet(spreadsheet, urlChecks, options) {
  // Build each row of output values in the order of the columns.
  const outputValues = [];
  for (const urlCheck of urlChecks) {

    if (options.saveAllUrls ||
        options.validCodes.indexOf(urlCheck.responseCode) == -1) {
      outputValues.push([
        urlCheck.customerId,
        new Date(urlCheck.timestamp),
        urlCheck.url,
        urlCheck.responseCode,
        urlCheck.entityType,
        urlCheck.campaign,
        urlCheck.adGroup,
        urlCheck.ad,
        urlCheck.keyword,
        urlCheck.sitelink
      ]);
    }
  }

  if (outputValues.length > 0) {
    // Find the first open row on the Results tab below the headers and create a
    // range large enough to hold all of the output, one per row.
    const headers = spreadsheet.getRangeByName(NAMES.RESULT_HEADERS);
    const lastRow = headers.getSheet().getDataRange().getLastRow();
    const outputRange = headers.offset(lastRow - headers.getRow() + 1,
                                     0, outputValues.length);
    outputRange.setValues(outputValues);
  }

  for (const email of RECIPIENT_EMAILS) {
    spreadsheet.addEditor(email);
  }
}

/**
 * Sends an email to a list of email addresses with a link to the spreadsheet
 * and the results of this execution of the script.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 * @param {boolean} numErrors The number of errors found in this execution.
 */
function sendIntermediateEmail(spreadsheet, numErrors) {
  spreadsheet.getRangeByName(NAMES.DATE_EMAILED).setValue(new Date());

  MailApp.sendEmail(
      RECIPIENT_EMAILS.join(','), `Link Checker Results`,
      `The Link Checker script found ${numErrors} URLs with errors in ` +
          `an execution that just finished. See ${
              spreadsheet.getUrl()} for details.`);
}

/**
 * Sends an email to a list of email addresses with a link to the spreadsheet
 * and the results across the entire account.
 *
 * @param {Object} spreadsheet The spreadsheet object.
 * @param {boolean} numErrors The number of errors found in the entire account.
 */
function sendFinalEmail(spreadsheet, numErrors) {
  spreadsheet.getRangeByName(NAMES.DATE_EMAILED).setValue(new Date());

  MailApp.sendEmail(
      RECIPIENT_EMAILS.join(','), `Link Checker Results`,
      `The Link Checker script found ${numErrors} URLs with errors ` +
          `across its entire analysis. See ${
              spreadsheet.getUrl()} for details.`);
}

/**
 * Retrieves all final URLs and mobile final URLs in the account across ads,
 * keywords, and sitelinks that were checked in a previous run, as indicated by
 * them having been labeled.
 *
 * @param {Object} options Dictionary of options.
 * @return {Object} A map of previously checked URLs with the URL as the key.
 */
function getAlreadyCheckedUrls(options) {
  const urlMap = {};

  function addToMap(items) {
    for (const item of items) {
      for(const url of expandUrlModifiers(item)){
        urlMap[url] = true;
      }
    }
  }

  if (options.checkAdUrls) {
    addToMap(getUrlsBySelector(AdsApp.ads()
                               .withCondition(labelCondition(true))));
  }

  if (options.checkKeywordUrls) {
    addToMap(getUrlsBySelector(AdsApp.keywords()
                               .withCondition(labelCondition(true))));
  }

  if (options.checkSitelinkUrls) {
    addToMap(getAlreadyCheckedSitelinkUrls());
  }

  return urlMap;
}

/**
 * Retrieves all final URLs and mobile final URLs for campaign and ad group
 * sitelinks.
 *
 * @return {Array.<string>} An array of URLs.
 */
function getAlreadyCheckedSitelinkUrls() {
  const urls = [];

  // Helper method to get campaign or ad group sitelink URLs.
  function addSitelinkUrls(selector) {
    const iterator = selector.withCondition(labelCondition(true)).get();

    for (const entity of iterator) {
      const sitelinks = entity.extensions().sitelinks();
      urls.push(...getUrlsBySelector(sitelinks));
    }
  }

  addSitelinkUrls(AdsApp.campaigns());
  addSitelinkUrls(AdsApp.adGroups());

  return urls;
}

/**
 * Retrieves all URLs in the entities specified by a selector.
 *
 * @param {Object} selector The selector specifying the entities to use.
 *     The entities should be of a type that has a urls() method.
 * @return {Array.<string>} An array of URLs.
 */
function getUrlsBySelector(selector) {
  const urls = [];
  const entities = selector.get();

  // Helper method to add the url to the list if it exists.
  function addToList(url) {
    if (url) {
      urls.push(url);
    }
  }

  for (const entity of entities) {
    addToList(entity.urls().getFinalUrl());
    addToList(entity.urls().getMobileFinalUrl());
  }

  return urls;
}

/**
 * Retrieves all final URLs and mobile final URLs in the account across ads,
 * keywords, and sitelinks, and checks their response code. Does not check
 * previously checked URLs.
 *
 * @param {Object} checkedUrls A map of previously checked URLs with the URL as
 *     the key.
 * @param {Array.<Object>} urlChecks An array into which the results of each URL
 *     check will be inserted.
 * @param {Object} options Dictionary of options.
 * @return {boolean} True if all URLs were checked.
 */
function checkUrls(checkedUrls, urlChecks, options) {
  let didComplete = true;

  // Helper method to add common conditions to ad group and keyword selectors.
  function addConditionsForAds(selector, includePaused) {
    const statuses = ['ENABLED'];
    if (includePaused) {
      statuses.push('PAUSED');
    }

    const predicate = ` IN (${statuses.join(',')})`;
    return selector.withCondition(labelCondition(false))
        .withCondition(`ad_group_ad.status${predicate}`)
        .withCondition(`campaign.status${predicate}`)
        .withCondition(`ad_group.status${predicate}`);
  }

  function addConditionsForKeywords(selector, includePaused) {
    const statuses = ['ENABLED'];
    if (includePaused) {
      statuses.push('PAUSED');
    }

    const predicate = ` IN (${statuses.join(',')})`;
    return selector.withCondition(labelCondition(false))
        .withCondition(`ad_group_criterion.status${predicate}`)
        .withCondition(`campaign.status${predicate}`)
        .withCondition(`ad_group.status${predicate}`);
  }

  if (options.checkAdUrls) {
    didComplete = didComplete && checkUrlsBySelector(checkedUrls, urlChecks,
        addConditionsForAds(AdsApp.ads()
                            .withCondition('CreativeFinalUrls != ""'),
                            options.checkPausedAds), options);
  }

  if (options.checkKeywordUrls) {
    didComplete = didComplete && checkUrlsBySelector(checkedUrls, urlChecks,
        addConditionsForKeywords(AdsApp.keywords()
                                 .withCondition('FinalUrls != ""'),
                                 options.checkPausedKeywords), options);
  }

  if (options.checkSitelinkUrls) {
    didComplete = didComplete && checkSitelinkUrls(checkedUrls, urlChecks,
        options);
  }

  return didComplete;
}

/**
 * Retrieves all final URLs and mobile final URLs in a selector and checks them
 * for a valid response code. Does not check previously checked URLs. Labels the
 * entity that it was checked, if possible.
 *
 * @param {Object} checkedUrls A map of previously checked URLs with the URL as
 *     the key.
 * @param {Array.<Object>} urlChecks An array into which the results of each URL
 *     check will be inserted.
 * @param {Object} selector The selector specifying the entities to use.
 *     The entities should be of a type that has a urls() method.
 * @param {!Object} options Dictionary of options.
 * @return {boolean} True if all URLs were checked.
 */
function checkUrlsBySelector(checkedUrls, urlChecks, selector, options) {
  const customerId = AdsApp.currentAccount().getCustomerId();
  const iterator = selector.get();
  const entities = [];

  // Helper method to check a URL.
  function checkUrl(entity, url) {
    if (!url) {
      return;
    }

    const urlsToCheck = expandUrlModifiers(url);

    for (const expandedUrl of urlsToCheck) {
      if (checkedUrls[expandedUrl]) {
        continue;
      }

      const entityType = entity.getEntityType();
      const entityDetails = {
        entityType: entityType,
        campaign: entity.getCampaign ? entity.getCampaign().getName() : '',
        adGroup: entity.getAdGroup ? entity.getAdGroup().getName() : '',
        ad: entityType == 'Ad' ? getAdAsText(entity) : '',
        keyword: entityType == 'Keyword' ? entity.getText() : '',
        sitelink: entityType.indexOf('Sitelink') != -1 ?
            entity.getLinkText() : ''
      };

      const responseCode = requestUrl(expandedUrl, options, entityDetails);

      urlChecks.push({
        customerId: customerId,
        timestamp: new Date(),
        url: expandedUrl,
        responseCode: responseCode,
        entityType: entityDetails.entityType,
        campaign: entityDetails.campaign,
        adGroup: entityDetails.adGroup,
        ad: entityDetails.ad,
        keyword: entityDetails.keyword,
        sitelink: entityDetails.sitelink
      });

      checkedUrls[expandedUrl] = true;
    }
  }

  entities.push(...iterator);

  for (const entity of entities) {
    checkUrl(entity, entity.urls().getFinalUrl());
    checkUrl(entity, entity.urls().getMobileFinalUrl());

    // Sitelinks do not have labels.
    if (entity.applyLabel) {
      entity.applyLabel(LABEL);
      checkTimeout();
    }
  }

  // True only if we did not breach an iterator limit.
  return entities.length === iterator.totalNumEntities();
}
/**
 * Retrieves a text representation of an ad, casting the ad to the appropriate
 * type if necessary.
 *
 * @param {Ad} ad The ad object.
 * @return {string} The text representation.
 */
function getAdAsText(ad) {
  // There is no AdTypeSpace method for textAd
  if (ad.getType() === 'TEXT_AD') {
    return ad.getHeadline();
  } else if (ad.isType().expandedTextAd()) {
    const eta = ad.asType().expandedTextAd();
    return eta.getHeadlinePart1() + ' - ' + eta.getHeadlinePart2();
  } else if (ad.isType().gmailImageAd()) {
    return ad.asType().gmailImageAd().getName();
  } else if (ad.isType().gmailMultiProductAd()) {
    return ad.asType().gmailMultiProductAd().getHeadline();
  } else if (ad.isType().gmailSinglePromotionAd()) {
    return ad.asType().gmailSinglePromotionAd().getHeadline();
  } else if (ad.isType().html5Ad()) {
    return ad.asType().html5Ad().getName();
  } else if (ad.isType().imageAd()) {
    return ad.asType().imageAd().getName();
  } else if (ad.isType().responsiveDisplayAd()) {
    return ad.asType().responsiveDisplayAd().getLongHeadline();
  } else if (ad.isType().responsiveSearchAd()) {
    return ad.asType()
        .responsiveSearchAd()
        .getHeadlines()
        .map(h => h.text)
        .join(', ');
  }
  return 'N/A';
}

/**
 * Retrieves all final URLs and mobile final URLs for campaign and ad group
 * sitelinks and checks them for a valid response code. Does not check
 * previously checked URLs. Labels the containing campaign or ad group that it
 * has been checked.
 *
 * @param {Object} checkedUrls A map of previously checked URLs with the URL as
 *     the key.
 * @param {Array.<Object>} urlChecks An array into which the results of each URL
 *     check will be inserted.
 * @param {Object} options Dictionary of options.
 * @return {boolean} True if all URLs were checked.
 */
function checkSitelinkUrls(checkedUrls, urlChecks, options) {
  let didComplete = true;

  // Helper method to check URLs for sitelinks in a campaign or ad group
  // selector.
  function checkSitelinkUrls(selector) {
    const iterator = selector.withCondition(labelCondition(false)).get();
    const entities = [];

    for (const iteratorElement of iterator) {
      entities.push(iteratorElement);
    }

    for (const entity of entities) {
      const sitelinks = entity.extensions().sitelinks();

      if (sitelinks.get().hasNext()) {
        didComplete = didComplete &&
            checkUrlsBySelector(checkedUrls, urlChecks, sitelinks, options);
        entity.applyLabel(LABEL);
        checkTimeout();
      }
    }

    // True only if we did not breach an iterator limit.
    didComplete = didComplete &&
        entities.length === iterator.totalNumEntities();
  }

  const statuses = ['ENABLED'];
  if (options.checkPausedSitelinks) {
    statuses.push('PAUSED');
  }

  const predicate = ` IN (${statuses.join(',')})`;
  checkSitelinkUrls(AdsApp.campaigns()
                    .withCondition(`campaign.status${predicate}`));
  checkSitelinkUrls(AdsApp.adGroups()
                    .withCondition(`ad_group.status${predicate}`)
                    .withCondition(`campaign.status${predicate}`));

  return didComplete;
}

/**
 * Expands a URL that contains ValueTrack parameters such as {ifmobile:mobile}
 * to all the combinations, and returns as an array. The following pairs of
 * ValueTrack parameters are currently expanded:
 *     1. {ifmobile:<...>} and {ifnotmobile:<...>} to produce URLs simulating
 *        clicks from either mobile or non-mobile devices.
 *     2. {ifsearch:<...>} and {ifcontent:<...>} to produce URLs simulating
 *        clicks on either the search or display networks.
 * Any other ValueTrack parameters or customer parameters are stripped out from
 * the URL entirely.
 *
 * @param {string} url The URL which may contain ValueTrack parameters.
 * @return {!Array.<string>} An array of one or more expanded URLs.
 */
function expandUrlModifiers(url) {
  const ifRegex = /({(if\w+):([^}]+)})/gi;
  const modifiers = {};
  let matches;
  let modifiedUrls;
  while (matches = ifRegex.exec(url)) {
    // Tags are case-insensitive, e.g. IfMobile is valid.
    modifiers[matches[2].toLowerCase()] = {
      substitute: matches[0],
      replacement: matches[3]
    };
  }
  if (Object.keys(modifiers).length) {
    let mobileCombinations;
    if (modifiers.ifmobile || modifiers.ifnotmobile) {
      mobileCombinations =
          pairedUrlModifierReplace(modifiers, 'ifmobile', 'ifnotmobile', url);
    } else {
      mobileCombinations = [url];
    }

    // Store in a map on the offchance that there are duplicates.
    const combinations = {};
    for (const url of mobileCombinations) {
      if (modifiers.ifsearch || modifiers.ifcontent) {
        for (const modifiedUrl of
            pairedUrlModifierReplace(modifiers, 'ifsearch', 'ifcontent', url)) {
          combinations[modifiedUrl] = true;
        }
      } else {
        combinations[url] = true;
      }
    }
    modifiedUrls = Object.keys(combinations);
  } else {
    modifiedUrls = [url];
  }
  // Remove any custom parameters
  return modifiedUrls.map(url => url.replace(/{[\w_+:]+}/g, ''));
}

/**
 * Return a pair of URLs, where each of the two modifiers is mutually exclusive,
 * one for each combination. e.g. Evaluating ifmobile and ifnotmobile for a
 * mobile and a non-mobile scenario.
 *
 * @param {Object} modifiers A map of ValueTrack modifiers.
 * @param {string} modifier1 The modifier to honour in the URL.
 * @param {string} modifier2 The modifier to remove from the URL.
 * @param {string} url The URL potentially containing ValueTrack parameters.
 * @return {Array.<string>} A pair of URLs, as a list.
 */
function pairedUrlModifierReplace(modifiers, modifier1, modifier2, url) {
  return [
    urlModifierReplace(modifiers, modifier1, modifier2, url),
    urlModifierReplace(modifiers, modifier2, modifier1, url)
  ];
}

/**
 * Produces a URL where the first {if...} modifier is set, and the second is
 * deleted.
 *
 * @param {Object} mods A map of ValueTrack modifiers.
 * @param {string} mod1 The modifier to honour in the URL.
 * @param {string} mod2 The modifier to remove from the URL.
 * @param {string} url The URL potentially containing ValueTrack parameters.
 * @return {string} The resulting URL with substitions.
 */
function urlModifierReplace(mods, mod1, mod2, url) {
  const modUrl = mods[mod1] ?
      url.replace(mods[mod1].substitute, mods[mod1].replacement) :
      url;
  return mods[mod2] ? modUrl.replace(mods[mod2].substitute, '') : modUrl;
}

/**
 * Requests a given URL. Retries if the UrlFetchApp QPS limit was reached,
 * exponentially backing off on each retry. Throws an exception if it reaches
 * the maximum number of retries. Throws an exception if the UrlFetchApp daily
 * quota limit was reached.
 *
 * @param {string} url The URL to test.
 * @param {!Object} options The options loaded from the configuration sheet.
 * @param {!Object} entityDetails Details of the entity, e.g. type, name etc.
 * @return {number|string} The response code received when requesting the URL,
 *     or an error message.
 */
function requestUrl(url, options, entityDetails) {
  let responseCode;
  let sleepTimeMillis = QUOTA_CONFIG.INIT_SLEEP_TIME_MILLIS;
  let numTries = 0;

  while (numTries < QUOTA_CONFIG.MAX_TRIES && !responseCode) {
    try {
      // If UrlFetchApp.fetch() throws an exception, responseCode will remain
      // undefined.
      const response = UrlFetchApp.fetch(url, {muteHttpExceptions: true});
      responseCode = response.getResponseCode();

      if (options.validCodes.indexOf(responseCode) !== -1) {
        if (options.useSimpleFailureStrings &&
            bodyContainsFailureStrings(response, options.failureStrings)) {
          responseCode = 'Failure string detected';
        } else if (options.useCustomValidation && !isValidResponse(url,
            response, options, entityDetails)) {
          responseCode = "Custom validation failed";
        }
      }

      if (THROTTLE_SECONDS > 0) {
        Utilities.sleep(THROTTLE_SECONDS * MILLISECONDS_PER_SECOND);
      }
    } catch(e) {
      if (e.message.indexOf('Service invoked too many times in a short time:')
          != -1) {
        Utilities.sleep(sleepTimeMillis);
        sleepTimeMillis *= QUOTA_CONFIG.BACKOFF_FACTOR;
      } else if (e.message.indexOf('Service invoked too many times:') != -1) {
        throw EXCEPTIONS.LIMIT;
      } else {
        return e.message;
      }
    }

    numTries++;
  }

  if (!responseCode) {
    throw EXCEPTIONS.QPS;
  } else {
    return responseCode;
  }
}

/**
 * Searches the body of a HTTP response for any occurrence of a "failure string"
 * as defined in the configuration spreadsheet. For example, "Out of stock".
 *
 * @param {!HTTPResponse} response The response from the UrlFetchApp request.
 * @param {!Array.<string>} failureStrings A list of failure strings.
 * @return {boolean} Returns true if at least one failure string found.
 */
function bodyContainsFailureStrings(response, failureStrings) {
  const contentText = response.getContentText() || '';
  // Whilst searching for each separate failure string across the body text
  // separately may not be the most efficient, it is simple, and tests suggest
  // it is not overly poor performance-wise.
  return failureStrings.some(
    failureString => contentText.indexOf(failureString) !== -1);
}

/**
 * Throws an exception if the script is close to timing out.
 */
function checkTimeout() {
  if (AdsApp.getExecutionInfo().getRemainingTime() < TIMEOUT_BUFFER_SECONDS) {
    throw EXCEPTIONS.TIMEOUT;
  }
}

/**
 * Returns the number of days between two dates.
 *
 * @param {Object} from The older Date object.
 * @param {Object} to The newer (more recent) Date object.
 * @return {number} The number of days between the given dates (possibly
 *     fractional).
 */
function dayDifference(from, to) {
  return (to.getTime() - from.getTime()) / (24 * 3600 * 1000);
}

/**
 * Builds a string to be used for withCondition() filtering for whether the
 * label is present or not.
 *
 * @param {boolean} hasLabel True if the label should be present, false if the
 *     label should not be present.
 * @return {string} A condition that can be used in withCondition().
 */
function labelCondition(hasLabel) {
  return `LabelNames ${(hasLabel ? `CONTAINS_ANY` : `CONTAINS_NONE`)}` +
      ` ["${LABEL}"]`;
}

/**
 * Retrieves an entity by name.
 *
 * @param {Object} selector A selector for an entity type with a Name field.
 * @param {string} name The name to retrieve the entity by.
 * @return {Object} The entity, if it exists, or null otherwise.
 */
function getEntityByName(selector, name) {
  const entities = selector.withCondition(`Name = "${name}"`).get();

  if (entities.hasNext()) {
    return entities.next();
  } else {
    return null;
  }
}

/**
 * Retrieves a Label object by name.
 *
 * @param {string} labelName The label name to retrieve.
 * @return {Object} The Label object, if it exists, or null otherwise.
 */
function getLabel(labelName) {
  return getEntityByName(AdsApp.labels(), labelName);
}

/**
 * Retrieves an AccountLabel object by name.
 *
 * @param {string} labelName The label name to retrieve.
 * @return {Object} The AccountLabel object, if it exists, or null otherwise.
 */
function getAccountLabel(labelName) {
  return getEntityByName(AdsManagerApp.accountLabels(), labelName);
}

/**
 * Checks that the account has all provided labels and creates any that are
 * missing. Since labels cannot be created in preview mode, throws an exception
 * if a label is missing.
 *
 * @param {Array.<string>} labelNames An array of label names.
 */
function ensureLabels(labelNames) {
  for (const labelName of labelNames) {
    const label = getLabel(labelName);

    if (!label) {
      if (!AdsApp.getExecutionInfo().isPreview()) {
        AdsApp.createLabel(labelName);
      } else {
        throw `Label ${labelName} is missing and cannot be created in ` +
            `preview mode. Please run the script or create the label manually.`;
      }
    }
  }
}

/**
 * Checks that the account has all provided account labels and creates any that
 * are missing. Since labels cannot be created in preview mode, throws an
 * exception if a label is missing.
 *
 * @param {Array.<string>} labelNames An array of label names.
 */
function ensureAccountLabels(labelNames) {
  for (const labelName of labelNames) {
    const label = getLabel(labelName);

    if (!label) {
      if (!AdsApp.getExecutionInfo().isPreview()) {
        AdsManagerApp.createAccountLabel(labelName);
      } else {
        throw `Account label ${labelName} is missing and cannot be ` +
            `created in preview mode. Please run the script or create the ` +
            `label manually.`;
      }
    }
  }
}

/**
 * Removes all provided labels from the account. Since labels cannot be removed
 * in preview mode, throws an exception in preview mode.
 *
 * @param {Array.<string>} labelNames An array of label names.
 */
function removeLabels(labelNames) {
  if (AdsApp.getExecutionInfo().isPreview()) {
    throw 'Cannot remove labels in preview mode. Please run the script or ' +
        'remove the labels manually.';
  }

  for (const labelName of labelNames) {
    const label = getLabel(labelName);

    if (label) {
      label.remove();
    }
  }
}

/**
 * Removes all provided account labels from the account. Since labels cannot be
 * removed in preview mode, throws an exception in preview mode.
 *
 * @param {Array.<string>} labelNames An array of label names.
 */
function removeAccountLabels(labelNames) {
  if (AdsApp.getExecutionInfo().isPreview()) {
    throw 'Cannot remove account labels in preview mode. Please run the ' +
        'script or remove the labels manually.';
  }

  for (const labelName of labelNames) {
    const label = getLabel(labelName);

    if (label) {
      label.remove();
    }
  }
}

/**
 * Validates the provided spreadsheet URL to make sure that it's set up
 * properly. Throws a descriptive error message if validation fails.
 *
 * @param {string} spreadsheeturl The URL of the spreadsheet to open.
 * @return {Spreadsheet} The spreadsheet object itself, fetched from the URL.
 * @throws {Error} If the spreadsheet URL hasn't been set
 */
function validateAndGetSpreadsheet(spreadsheeturl) {
  if (spreadsheeturl == 'YOUR_SPREADSHEET_URL') {
    throw new Error('Please specify a valid Spreadsheet URL. You can find' +
        ' a link to a template in the associated guide for this script.');
  }
  return SpreadsheetApp.openByUrl(spreadsheeturl);
}

/**
 * Validates the provided email address to make sure it's not the default.
 * Throws a descriptive error message if validation fails.
 *
 * @throws {Error} If the list of email addresses is still the default
 */
function validateEmailAddresses() {
  if (RECIPIENT_EMAILS && RECIPIENT_EMAILS[0] == 'YOUR_EMAIL_HERE') {
    throw new Error('Please either specify a valid email address or clear' +
        ' the RECIPIENT_EMAILS field.');
  }
}